This invention relates to a wafer-level hermetic package for a micro device.
A micro-size cap (xe2x80x9cmicrocapxe2x80x9d) wafer-level package is formed by bonding a cap wafer to a device wafer. The bonding areas are seal rings formed around each die and vias for receiving via contacts or plugs. Due to leaks from defects or contamination in the bonding areas, a packaged device may fail quality and reliability tests where it is exposed to high temperature and humidity. Thus, what is needed is a method to enhance the seal to increase the final product yield.
In one embodiment of the invention, a method for forming a wafer package includes forming a die structure, wherein the die structure includes a first wafer, a device mounted on the first wafer, a second wafer mounted atop the first wafer with a first seal ring around the device and a second seal ring around a via contact. The method further includes forming a trench in the second wafer around the first seal ring, filling the trench and the via contact with a sealing agent, patterning a topside of the second wafer to remove the excessive sealing agent and to expose a contact pad of the via contact, and singulating a die around the first seal ring.